Kathmandu — Scientists have identified a range of proteins that can be used as reliable indicators of a person's nutrient levels. The discovery means portable nutrient-measuring devices could be developed that could aid understanding of malnutrition among the world's poor.
The body needs only tiny concentrations of certain substances, which include metals such as copper and selenium and vitamins A and D, but many people in the developing world have deficiencies in such micronutrients.
Although it is possible to quantify individual nutrient levels with chemical tests, populations in the developing world often lack a broad range of nutrients. This means several different tests may be needed, making it difficult and time-consuming to obtain a complete and accurate picture of people's nutritional health.
Now a study, published in the current issue of The Journal of Nutrition, shows that this 'hidden hunger' can be assessed more comprehensively using quantitative proteomics. This approach measures thousands of protein concentrations in blood samples, looking for correlations with nutrient levels. If correlations are found then protein levels can be used to easily calculate nutrient levels.
The idea was outlined at an August conference in Kathmandu, Nepal, organised by Feed the Future Innovation Lab for Collaborative Research on Nutrition, a research project funded by the US Agency for International Development.
The study's lead author, Keith West Jr, director of the Centre for Human Nutrition at Johns Hopkins University, Baltimore, United States, explains that his team's approach to micronutrient assessment is based on the principle that each nutrient has a set of proteins that bind to it and escort it through the different stages of metabolism.
"We assume that the levels of protein we find in the blood reflect the levels of nutrients in the body," he says.
During their study the team chemically tagged thousands of proteins in a subject's blood sample and measured their relative concentrations using a technique called mass spectrometry. Using this method, West and his colleagues have established positive correlations between some important micronutrients - including copper, selenium and vitamins A, D and E - and their corresponding proteins.
"Now these proteins are known to predict micronutrient status, it may be possible to develop portable devices for micronutrient testing - something that can sit in a lab in Kathmandu rather than a lab in Baltimore, for instance," says West.
The prospect of having portable devices to test for micronutrients could be a welcome innovation for nutrition programmes run by NGOs in countries that lack accredited labs to do this, according to Naveen Paudyal, a nutrition officer at the UN Children's Fund (UNICEF) in Nepal.
"If simple and accessible technologies for testing micronutrients are available, then that would be very supportive for us," she tells SciDev.Net. "We find sending samples abroad to be very inconvenient."